Patents; A blood cell therapy is designed to act as a decoy to lure HIV away from the immune cells it kills.

By Sabra Chartrand

Published: August 30, 1993

WASHINGTON—
MEDICAL researchers around the world are racing to develop new treatments for AIDS, hoping to find a cure or vaccine. Yet an antidote to HIV, the virus that causes AIDS, is probably years away, and may come as a combination of medications rather than a single remedy.

One technique could be a new red blood cell therapy patented this month by Sheffield Medical Technologies Inc. Based on work done at the Harvard Center for Blood Research by Dr. Yves-Claude Nicolau, the invention inserts a protein called CD4 into red blood cells to lure HIV away from the human immune cells that it kills.

The CD4 protein appears naturally on the surface of human immune cells, called T-cells. HIV binds to the protein, infects the T-cells, kills them and then reproduces itself. But HIV cannot differentiate between the protein appearing on T-cells or on red blood cells.

So in the new patent, the CD4 protein is "embedded in the red blood cells' surface much like a pin in a pin cushion, with the head sticking out," said the president of Sheffield, Douglas R. Eger. He said 1,600 proteins are embedded in each red blood cell through an electric shock process. The process causes the cells to come apart temporarily so the CD4 can be inserted with each receptor site facing out, "like a docking site." A Virus Decoy

When these cells are added to HIV-infected blood, the HIV aims for the CD4 on the red blood cells.

"What normally appears on the T-cells now shows up on the red blood cells," Mr. Eger said. "So it's decoying the virus away."

The red blood cells are fatal to HIV.

"There's no nucleus in a red blood cell, so there's nothing for it to infect -- so it dies," Mr. Eger said. Red blood cells have a life span of 120 days, so eventually the body breaks down the cells carrying the inert HIV.

"We may be able to clean the blood of the virus," Mr. Eger said, cautioning that this is not a cure for AIDS. "New viruses can come from the lymph nodes or from the bone marrow or the brain of an infected person -- places the bloodstream can't get at.

"If we can sponge these viruses up, then we'll have an extremely effective therapeutic treatment, but not a cure," he said.

Sheffield cannot say whether the CD4 red blood cell treatment will be effective. But Mr. Eger said his company was encouraged by clinical trials that indicated the protein was not toxic and that the HIV did not re-infect the blood when the old red blood cells were broken down.

The company plans to begin tests on humans in January. But even if the treatment proves effective, it will probably take several years to obtain approval from the Food and Drug Administration. Mr. Eger said each dose would probably cost several thousand dollars because of the high cost of producing CD4, which is made from caterpillar cells. Sheffield's patent is 5,236,835. Applicator to Make Condom Use Easier

One effective way to control sexual transmission of HIV is through the use of condoms. A New Jersey inventor said he hoped condom use would be easier with an applicator.

Daniel Swisher, a consumer products designer, patented the applicator after volunteering as a counselor to young people engaged to be married. He said he discovered that many of them did not use condoms because they found them messy and inconvenient.

Mr. Swisher's invention is a small case that holds a condom package, cuts it open and allows the user to put the condom on without having to touch it. It is small enough to be carried in a purse or pocket.

The case opens like a compact. An octagonal blade inside the lid cuts open the condom wrapper all around the prophylactic.

"You put the condom package in it, and when you snap it shut -- that's when the cutting device cuts through the package," Mr. Swisher said.

In the next step, the condom wrapper is removed. "When you go to use it, you pop open a tiny door on the bottom that has adhesive on it that takes away the bottom of the packaging," Mr. Swisher said.

"When you pull the top lid up and begin application, the top of the packaging pops off," he added.

Then the case acts like a ring, holding the condom in place as it is applied.

"There's a foam rubber seal that holds the rolled lip of the condom as you apply it," Mr. Swisher said. "When the condom is fully unrolled, the device slides right off."

Mr. Swisher said he hoped to get a development grant from the Federal Centers for Disease Control and Prevention in Atlanta, where his device is now under evaluation.

"There are lots of problems in trying to get young people to use condoms," he said. "It's a problem for the center for disease control. So they're looking at this as a different method for teaching."

Mr. Swisher's patent is 5,238,103. New Mailbox Signal Saves a Long Walk

For those who live in apartment buildings, new suburbs or on farms, collecting the mail may involve a walk to the box just to check for delivery. That chore could be eliminated by a new mailbox signaling system that works like a hotel room message light.

"Basically it's a transmitter similar to a transmitter used to open a garage door," said John Shea, an engineer from Connecticut who designed the device with Colleen Murphy, who plans to manufacture and market the system.

"When the mailbox door is opened, it sends a pulse that goes to a receiver in the house," he said. "In the house, a buzzer sounds for 10 seconds and a light lights up."

The light remains on until someone pushes an adjacent reset button.

"This may sound trivial, but there's also a reset button on the mailbox," Mr. Shea said. "That's important because if you put outgoing mail in the box, the buzzer buzzes and the light lights. But it's you, not the mailman. So you can hit the reset button at the box yourself."

The battery-operated transmitter attaches to the inside of the mailbox. It is about the size of a television remote control unit, and, Mr. Shea said, its signal can travel about a quarter of a mile, or up "a couple of high-rises." It received patent 5,239,305.

Patents are available by number for $3 from the Patent and Trademark Office, Washington, D.C. 20231.